Virtual simulation of spatial audio characteristics

ABSTRACT

Embodiments of the present invention are directed to a system and method for demonstrating spatial performance of a demonstration speaker model to consumers in order to evaluate different speakers. The system and method comprise a microphone array for recording the output of the demonstration speaker model. The system and method comprise acoustic input samples for processing to an acoustic output and a processor for determining characteristics of each microphone recording, and processing an acoustic input sample and characteristics of each microphone recording corresponding to a selected demonstration speaker model. The system and method further comprise a reference speaker model for outputting an acoustic signal based on the result of the processing. The processing compensates for the performance characteristic of the reference speaker and the performance characteristic of the selected demonstration speaker so as to mimic the spatial characteristics of the demonstration speaker while avoiding bias from the reference speaker.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of, and claims priority toU.S. Utility patent application Ser. No. 16/880,623, filed May 21, 2020,which is a continuation of, and claims priority to U.S. Utility patentapplication Ser. No. 16/380,015, filed Apr. 10, 2019, now U.S. Pat. No.10,667,070, which is a continuation of, and claims priority to, U.S.Utility patent application Ser. No. 16/132,769, filed Sep. 17, 2018, nowU.S. Pat. No. 10,284,990, which is a continuation of, and claimspriority to, U.S. Utility patent application Ser. No. 15/491,037, filedApr. 19, 2017, now U.S. Pat. No. 10,091,602, which is a continuation of,and claims priority to, U.S. Utility patent application Ser. No.14/709,650, filed May 12, 2015, now U.S. Pat. No. 9,674,633, whichclaims priority to U.S. Provisional Application No. 61/992,542, filedMay 13, 2014. Each of these related applications is hereby incorporatedby reference herein in its entirety.

FIELD OF THE INVENTION

The present invention relates to measuring and simulating the spatialcharacteristics of a sound source, such as an audio speaker. Morespecifically, the invention relates to simulating how a demonstrationsounds in different points in space.

BACKGROUND OF THE INVENTION

As illustrated in FIG. 1, systems and methods exist that allow retailoutlets to use a reference speaker to demonstrate the performance ofmultiple demonstration speakers. For example, the Virtual SpeakerDemonstration System And Virtual Noise Simulation disclosed in U.S. Pat.Nos. 7,096,169 and 7,899,656, incorporated herein by reference, enablesa customer to simulate the performance of a particular demonstrationspeaker using a reference speaker. These virtual speaker demonstrationsystems simulate the output of the selected demonstration speaker bydetermining characteristics of the demonstration speaker and applyingthese characteristics to a sample acoustic input.

Significantly, however, the characteristics of a demonstration speakerare typically derived (empirically or analytically) without regard toits spatial characteristics. That is, retailers often empiricallydetermine the characteristics of a demonstration speaker by measuringits transfer function at a single point in space. FIG. 1 illustrates anexemplary prior art embodiment, where a single microphone 102 is used tomeasure a transfer function of the demonstration speaker at a singlepoint in space. Although such a transfer function may be used tosimulate a demonstration speaker, the transfer function will not be anaccurate representation of how the demonstration speaker would sound atany other point in space.

Audio enthusiasts understand that a key driver of sound quality in audioequipment is how sound waves disperse from a sound source. For example,acoustic phenomena such as speaker directivity, interaction betweenmultiple drivers, and diffraction affect which frequencies of sound canbe heard at different distances or angles from a speaker. Directivity,for instance, characterizes a speaker's ability to emit differentspectral frequencies of an audio signal in one particular direction. Inall wave-producing sources, the directivity of any source generallycorresponds to the size of the source compared to the wavelengths it isgenerating. Thus, loudspeakers tend to radiate sound omnidirectionally(i.e., uniformly in all directions) at low frequencies, because thephysical components of the speaker, such as surface dimensions andcabinetry, are generally small compared to the wavelength of the sound.However, at high frequencies, speakers tend to beam the sound, becausethe physical components of the speaker are no longer negligible ascompared to the sound's wavelength. Thus, speakers typically generate a“beam” of high spectral frequencies directly in front of a speaker,while lower bass-like frequencies may be perceived both in front, andbehind a speaker. Further complexities may be added to the speaker'sspatial characteristics when multiple drivers are radiating in the samefrequency range, such as the crossover region, and when acousticdiffraction occurs due to physical discontinuities, such as at the edgesof the speaker cabinet. More generally, each loudspeaker radiates adifferent spectrum of frequencies at different angles off of its centralaxis (off-axis). Accordingly, each loudspeaker has a distinct transferfunction that depends on the listener's location in space. Consequently,listeners located at different positions around a speaker will each heara different spectrum of sound, even though they are each listening tothe same speaker.

Directivity, and other similar spatial characteristics, may berepresented as directivity patterns, illustrated in FIGS. 2A and 2B.FIG. 2A is an exemplary polar plot that illustrates the frequency gainof a demonstration speaker for a particular frequency (e.g., 10 kHz)across a 360° rotation around the demonstration speaker. As FIG. 2Aillustrates, the frequency response has higher gain due to beam-formingin front of the speaker, while less energy radiates to the rear. FIG. 2Bis an exemplary directivity plot illustrating how a speaker may havedifferent frequency response gains at different frequencies, and atdifferent angles off of the speaker's center axis. For example, afrequency of 125 Hz may have a gain of −3 dB at 90°, whereas a frequencyof 1.6 kHz may have a gain of −9 dB at 90°. As these figures illustrate,the transfer function of a speaker may vary drastically as it ismeasured throughout different points in space. As stated above,listeners consequentially hear different spectrums of frequencies atdifferent points in space.

Differences in the build of the speakers, such as shape, material,dimensions, and placement of components (e.g., the transducer) in thecasing, may also affect the ability of the speaker to project, i.e.,“throw”, a sound wave at varying distances from the speaker in acoherent fashion. As with directivity, the dispersion of the sound wavefrom the speaker depends on the frequency of the sound wave, thetechnical specifications of the speaker driver, and the dimensions(e.g., shape size, positioning, etc.) of the speaker horn As a result,audio enthusiasts generally understand that two different speakers mayexhibit different sound quality as a result of how sound waves dispersefrom the speakers, i.e., the spatial characteristics of the speakers.

Although audio retailers are generally aware that different speakersdisperse sound differently (reflecting a difference in sound quality),audio retailers typically do not provide an effective way to demonstratethis difference to audio consumers. As noted above, prior demonstrationsystems such as those disclosed in U.S. Pat. Nos. 7,096,169 and7,899,656 and implemented in Crutchfield's Virtual Speaker System, aregenerally limited to the acoustic performance of speakers as measuredfrom a single point in space. As FIG. 1 illustrates, acousticcharacteristics (e.g., frequency responses and transfer functions) of aspeaker are typically measured from a single point in space, 102, inrelation to the speaker. This single data point is then applied to areference speaker 106 to simulate the performance of the demonstrationspeaker 101. Accordingly, demonstration systems currently provided byaudio retailers typically do not demonstrate the spatial performance ofa speaker, i.e., the impact of sound quality due to the dispersion ofthe sound waves from the speaker, because the acoustic characteristicsare only measured from a single point in space.

For one, audio retailers do not have an efficient means for empiricallymeasuring spatial characteristics at multiple points in space.Typically, determining directivity pattern is time and resourceintensive, usually requiring a retailer to make discrete sequentialmeasurements of a speaker's transfer function at different angles aroundspeaker. While systems such as microphone arrays exist, which enableretailers to make several simultaneous measurements of a speaker'stransfer function in space, several drawbacks exist. Microphone arraysare generally applied to problems in two categories of acoustics: 1)beam-forming; and 2) near-field acoustic holography (“NAH”).Beam-forming microphone arrays process the microphone signals in a waythat causes the array system to be more sensitive to sound coming fromone particular direction. NAH is concerned with using acousticmeasurements to determine the vibration of an acoustically radiatingsurface. Significantly, these applications of microphone arrays are nottypically designed to capture the spatial performance characteristics ofa loudspeaker.

Even where audio retailers have spatial characteristics measured frommultiple points in space, problems exist in combining speakercharacteristics to effectively simulate these spatial characteristics tousers. Electro-acoustic modeling software packages (such as EASE®,MEYER®, or ANSYS®) provide analytic acoustic information (e.g.,directivity and dispersion). However, these modeling software packagesare generally time and resource-intensive to use. Accordingly, anefficient means for measuring the acoustic characteristics of any soundsource, and simulating the sound source with empirical data is needed.

Further problems exist with combining different empirically derivedspatial characteristics. When combining and processing characteristicsfrom multiple sources at different points in space, the oscillatorybehavior, thus the complex nature of the data, must be carefullyconsidered to avoid introducing unrealistic distortions. Accordingly, anefficient means for combining the acoustic characteristics measurementsof sound sources while minimizing the introduction of distortions isneeded. Other problems and drawbacks also exist.

Even when the empirically derived spatial characteristics are suitablycombined, simulation errors remain due to the single degree of freedom(SDOF) afforded by the traditional reference speaker. The remainingerror is due to the difference in acoustic spatial radiation patternsbetween the target simulation speaker and the reference speaker used toperform the simulation. Thus, there exists a need for a multi-degree offreedom (MDOF) reference speaker, such as a speaker array consisting ofseveral acoustic drivers that may allow the control over the referencespeaker's spatial radiation pattern, and in turn, allow accuratesimulation of the target simulation speaker's temporal and spatialcharacteristics simultaneously.

SUMMARY OF THE INVENTION

Embodiments of the present invention comprise a virtual speakerdemonstration system that permits a retail outlet to measure thetemporal and spatial characteristics of a demonstration speaker. Thetemporal and spatial characteristics of a demonstration speaker may bemeasured at multiple points in space. These characteristics may includetransfer functions, impulse responses, and similar mathematicalfunctions. The characteristics may be combined into a singlecharacteristic representative of the speaker's spatial audiocharacteristics. The measured characteristics may then be used to derivethe output to a traditional reference speaker or the outputs to aspeaker array to simulate the spatial characteristics of thedemonstration speaker.

BRIEF DESCRIPTION OF THE DRAWINGS

The objectives and advantages of the present invention will be apparentto those of skill in the art from the following detailed description inconjunction with the appended drawings in which like referencecharacters are used to indicate like elements, and in which:

FIG. 1 is a diagram of a virtual demonstration system according to priorart systems and methods.

FIGS. 2A and 2B are exemplary directivity patterns of a speaker.

FIG. 3 is an exemplary virtual demonstration system for spatial audiocharacteristics according to one embodiment of the invention.

FIG. 4 is an illustration of the spatial audio characteristics stored inthe virtual demonstration system according to one embodiment of theinvention.

FIG. 5 is an illustration of the front view of a microphone array in avirtual demonstration system according to one embodiment of theinvention.

FIG. 6 is an illustration of the front view of a plurality of microphonearrays in a virtual demonstration system according to another embodimentof the invention.

FIG. 7 is an illustration of an arrangement of microphone arrayssurrounding a demonstration speaker according to another embodiment ofthe invention.

FIG. 8 is an illustration of the top view of a microphone arraysuperimposed over a directivity pattern according to one embodiment ofthe invention.

FIG. 9 is an illustration of a DSP combining characteristics for playingsamples on a reference speaker according to one embodiment of theinvention.

FIG. 10 is a diagram of a speaker array according to one embodiment ofthe invention.

FIG. 11 is a block diagram of an exemplary user interface according toan embodiment of the invention.

FIG. 12 is a block diagram of the exemplary characteristics that may beused by the virtual demonstration system.

FIG. 13 is a block diagram of the digital signal processing that may beemployed for the virtual demonstration according to an embodiment of theinvention.

FIG. 14 is a flow diagram of a method for a user to engage the virtualdemonstration system according to an embodiment of the invention.

FIG. 15 is a flow diagram of a method creating a virtual demonstrationaccording to an embodiment of the invention.

FIG. 16 is a block diagram of the loudspeaker characteristics that maybe employed for the virtual demonstration according to an embodiment ofthe invention.

FIG. 17 is a block diagram of environmental conditions that may beemployed for the virtual demonstration according to an embodiment of theinvention.

FIG. 18 is a block diagram of a system for a virtual demonstrationsystem according to an embodiment of the invention.

FIG. 19 is a block diagram of an interface for a user to initiate avirtual environmental factors simulation according to an embodiment ofthe invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 3 is a diagram of the virtual demonstration system according to anembodiment of the invention. The virtual demonstration system includes ademonstration speaker 301, a microphone array 302, a digital signalprocessor (DSP) 303, characteristics 304, samples 305, a referencespeaker 306, and an interface 307.

Generally, the operation of the spatial demonstration system is asfollows. A user, such as an audio equipment retailer, wishing tosimulate the performance of audio/stereo equipment, such as a speaker,measures the spatial characteristics of the audio/stereo equipment. Theuser measures the characteristics by positioning a demonstration speaker301 near a microphone array 302. A microphone array 302 may support anumber of microphones N, N+1, N+2, N+3, etc., for recording the outputof the demonstration speaker at different points in space. In anembodiment of the invention, the microphone array 302 may be comprisedof one microphone. In an embodiment of the invention, the microphonearray 302 may be comprised of multiple microphones. FIG. 3 depicts aprofile view of the microphone array according to one embodiment of theinvention. As discussed in more detail below, the microphones may bespaced along the microphone array in a number of different axes,directions, and positions. According to some embodiments of theinvention, the acoustic characteristics are measured using a microphonearray. In embodiments of the invention, each microphone is preferablydesigned to receive and measure omnidirectional sound waves.

The user applies an input signal, such as a song, to the demonstrationspeaker 301. The demonstration speaker 301 plays the song, emittingsound waves according to the demonstration speaker's inherent spatialcharacteristics. That is, inherent qualities of the demonstrationspeaker 301, such as the materials, diaphragm, etc., will affect how thesound waves disperse from the speaker. Thus, for example, differentfrequencies of the song may be heard with different loudness atdifferent points in space around the speaker. Each microphone N, N+1,N+2, etc., in the microphone array 302 captures the output of thedemonstration speaker 302 at different points in space. The outputcaptured by each microphone is then sent to the DSP 303 as input signalsINPUT N, INPUT N+1, INPUT N+2, INPUT N+3, etc. According to someembodiments of the invention, the DSP 303 includes a data acquisitionsystem, such as the National Instruments DAQ PXI Platform®, foracquiring the signals output by each microphone. Each microphonesupported by the microphone array 302 may be coupled to the dataacquisition system via communication and connection ports well known inthe art, such as 0.8 mm, S-100, or XLR cable connection, or similarwired or wireless network connection.

The DSP 303 acquires the microphone input signals and determines thecharacteristics 304 of each input signal. Characteristics 304 generallyrefer to transfer functions, impulse responses, or other mathematicaldescriptions that characterize acoustic performance. Characteristics 304may be used to characterize and, therefore, account for, the effects ofvarious components of an acoustic system on overall acousticperformance. For example, characteristics 304 may be characteristics fordemonstration speakers, reference speakers, demonstration spaces (roomsor vehicle interiors), reference spaces (e.g., the listening room in aretail outlet where the virtual demonstration is presented), amplifiers,tuner/receivers, equalizers, and so forth. Additionally, in a beneficialembodiment allowing the user to “build” his/her own demonstration space,characteristics 304 may include absorption parameters for variousmaterials and geometry parameters which can be used to create ademonstration room.

Using digital signal processing techniques, DSP 303 determines thecharacteristics 304. According to some embodiments of the invention, asdiscussed in more detail below, a characteristic is determined for eachmicrophone input signal, INPUT N, INPUT N+1, . . . , etc. In this way,the DSP may determine the characteristics of the demonstration speaker301 at several points in space. According to other embodiments of theinvention, the DSP may combine the characteristics of each microphoneinput signal into a single characteristic using digital processingtechniques discussed in more detail below. According to otherembodiments of the invention, the DSP may utilize the microphone inputsignals to determine the set of output signals for a speaker array toreproduce the characteristics of the demonstration speaker 301. Forexample, the DSP may use the microphone signals to perform a Filtered-XLeast Mean Square Adaptive Filter algorithm to compute the filtercoefficients that determine the reference speaker output or set offilter coefficients that determine the speaker array outputs.

A retailer may store a database of different spatial characteristics foreach demonstration speaker in their inventory. According to someembodiments, spatial characteristics may be determined for each make,model, year, or similar manufacturing parameters of the speaker. Spatialcharacteristics may further be determined for various differentenvironmental characteristics (e.g., a room or an interior of a vehicle)or environmental conditions (e.g., vehicle speed, windows open/closed,etc.). For example, to simulate how a speaker may sound at variousdifferent distances from a listener, the spatial characteristics of thespeaker may be measured at various distances between the demonstrationspeaker and microphone array. According to some embodiments, thedatabase of spatial characteristics for various different demonstrationspeakers may be stored in DSP 303. In other embodiments, the spatialcharacteristics may be stored externally to the DSP, such as on acomputer, server, or a computer readable storage medium (not pictured)that stores non-transitory data signals, including magnetic storagemedia (for example, ROMs, floppy discs, hard disks, etc.), oroptically-readable media (for example, CD-ROMs, VDs, etc.). Distinctfrom computer readable storage medium, the spatial characteristics mayalso be stored in transmission media that stores transitory signals,such as data signals embodied in carrier waves (e.g., transmittedthrough a network).

A customer may simulate a particular make and/or model of loudspeaker bychoosing the characteristics for the loudspeaker via interface 307. Theuser may navigate the interface by selecting various options. Theoptions may include parameters such as the make, the model,environmental characteristics, environmental conditions, and othersfurther described below. The options may also include basic start (e.g.,“Start Virtual Demonstration”), play (e.g., “Play VirtualDemonstration”), and stop (e.g., “End Virtual Demonstration”) options.The interface 307 may include a keyboard, touch screen, voicerecognition module, mouse or similar point-and-click device, or anysimilar device usable for inputting selections.

Samples 305 are acoustic samples, such as samples of music, test sounds,spoken voice, etc. According to one approach, samples 305 are pre-storedin the virtual demonstration system and selected by the user viainterface 307. According to another approach, samples 305 may be inputby the user externally, for example via a physical computer readablestorage device, such as a CD, DVD, USB drive, or similar device, or anetwork connection, such as Ethernet, Wi-Fi, Bluetooth, or similarnetwork connection for inputting acoustic samples to the demonstrationsystem.

The user may run the virtual spatial demonstration by applying theuser-selected options to the user-selected input. Using digital signalprocessing techniques discussed in more detail below, DSP 303 processesthe user-selected characteristics 304 and acoustic samples 305 toproduce an output representative of how the input would sound beingplayed from the selected demonstration speakers. This output may then beplayed through reference speaker 306.

The user can then run the virtual spatial demonstration again byselecting different options, such as a different set of demonstrationspeakers, a different environment, a different amplifier, and so forth.In each case, the user will be hearing the virtual output at anylocation within the reference environment (i.e., the listening room)through the same reference speakers, thus permitting a convenient andfair (“apples to apples”) comparison.

The virtual system of FIG. 3 is presented in simplified form in order tohighlight the unique features of the invention. It should be understoodthat the virtual system may include various conventional operations,such as anti-aliasing filtering, digital-to-analog conversion (DAC),amplification, and various signal conditioning processes, beforeoutputting the virtual signal through reference speakers 306. The signalprocessing performed by DSP 303 in order to implement the invention iswell understood in the art.

Generally, characteristics of speakers, environments, amplifiers, andother components of the total acoustic system can be expressed astransfer functions (frequency domain) or impulse responses (time domainequivalent of the transfer function). These transfer functions can bedetermined analytically (through modeling and prediction, such as raytracing) or empirically (through measurement). In a preferred embodimentof the invention, the transfer functions are determined empirically.

For example, transfer functions of the various demonstration speakerssupported by the virtual system can be measured in an anechoic chamberby stimulating the speakers with a basic acoustic input and themeasuring the response. Preferably, the response is measured across afrequency spectrum of interest to users, such as about 5 Hz to 30,000Hz, which goes beyond the typical range of human hearing but which willinclude the vibratory effects at the low and high ends. Because themicrophone array captures sound emitted from the demonstration speakerat multiple points in space, the measurement of the transfer functionmay be made at multiple angles with respect to the demonstration speaker(to derive a response which is a function of angle).

According to one embodiment of the invention, the transfer functions ofboth the demonstration speakers and the reference speakers are measured.This permits the effects of the reference speakers to be removed and theeffects of the selected demonstration speaker to be inserted.

The transfer functions of the environments can be measured in analogousfashions. For example, the virtual system may include options forvarious demonstration environments (rooms or vehicle interiors). Thetransfer functions for these demonstration environments can bedetermined analytically or empirically. If determined analytically, raytracing or other acoustic modeling techniques are used to predict animpulse response for an analytic demonstration environment defined bygeometric parameters, materials, and sound absorption/reflectionparameters. If determined empirically, actual demonstration environmentsare employed and then stimulated with a known acoustic input through aspeaker or transducer with known transfer characteristics. The impulseresponse of the demonstration environment can then be extracted usingwell known principles of acoustic signal processing.

According to one embodiment of the invention, the transfer functions ofboth the demonstration environment and the reference environment aremeasured. This permits the effects of the reference environment to beremoved and the effects of the selected demonstration environment to beinserted.

The transfer functions of other components in the overall acousticsystem can be determined in analogous fashions. For example, the virtualdemonstration system may include a reference amplifier for powering thedemonstration, but the user may be allowed to select a demonstrationamplifier. For example, the user might want to comparatively assess theperformance of speaker set 1 versus speaker set 2 where each is poweredby amplifier X. In order to support this capability, the virtualdemonstration system may provide for the transfer characteristics ofvarious demonstration amplifiers (note: amplifiers is construed broadlyhere, and could include receivers or separate amplifier/tuners) to bepredicted/measured (or provided by a manufacturer) and stored.Preferably, the transfer characteristics of the reference amplifier areknown and can be removed before the characteristics of the selecteddemonstration amplifier are inserted. DSP 303 performs the digitalsignal processing to produce the simulation output.

DSP 303 may be a processor, microprocessor, microcontroller, computer,or similar device. The principles behind the operations performed by DSP303 are well understood in the art. The reader is referred to thefollowing texts for background on signal processing operations (e.g.,inverse filtering, compensation, time domain filtering, frequency domainfiltering, and so forth) that may be used to implement the invention: A.V. Oppenheim & R. W. Schafer, Digital Signal Processing (Prentice-Hall:1975); B. Widrow & S. D. Steams, Adaptive Signal Processing(Prentice-Hall: 1985); P. A. Nelson & S. J. Elliot, Active Control ofSound (Harcourt Brace: 1992); J. S. Bendat and 65 A. G. Piersol, RandomData (John Wiley & Sons: 1986); Reference Data for Engineers, 9'h ed.(Butterworth-Heinmaun: 2002); and L. R. Rabiner & R. W. Schafer, DigitalProcessing of Speech Signals (Prentice-Hall: 1978). Exemplary operationsthat may be performed by DSP 303 are discussed further in connectionwith FIG. 13.

FIG. 4 is a block diagram illustrating the details of the acquisitionand processing of the microphone input signals according to oneembodiment of the invention. Microphones N, N+1, N+2, N+3, etc., capturethe output of the demonstration speaker as input signals, INPUT N, INPUTN+1, INPUT N+2, INPUT N+3, etc. The DSP acquires the microphone inputsignals and processes them using the digital processing techniquesdescribed above to determine CHARACTERISTIC N, CHARACTERISTIC N+1,CHARACTERISTIC N+2, CHARACTERISTIC N+3, etc. As FIG. 4 illustrates,characteristics may be expressed as transfer functions (frequencydomain) or impulse responses (time domain equivalent of the transferfunction). FIG. 4 depicts a bode plot of the transfer functions of eachmicrophone input signal, illustrating the magnitude of the frequencyresponse gain, or frequency response phase shift as a function offrequency. In this way, the DSP determines the transfer function of thedemonstration speaker at several different points in space.

FIG. 5 illustrates a frontal view of the microphone array 502 accordingto one embodiment of the invention. The microphones supported by thearray may be arranged in any particular plane. FIG. 5 depicts oneexemplary arrangement, where the microphones 502 a . . . 502 n″ arearranged across the plane facing the demonstration speaker 501 (i.e.,the X-Y plane). According to one embodiment, the microphones 502 a . . .502 n″ may be arranged evenly across the plane, such as for example,every three inches apart in the X-direction, and every 4 inches apart inthe Y-direction. In this way, the spatial demonstration system maydetermine characteristics of the demonstration speaker 501 at anyheight, or angle from the speaker. According to some embodiments, themicrophones 502 a . . . 502 n″ may be placed at positions correspondingto the positions of the speaker components. For example, microphones maybe placed at the same heights as a speaker's 501 tweeter and woofer.

FIG. 6 illustrates the spatial demonstration system according to oneembodiment of the invention where microphones 602 a . . . 602 n″ and 603a . . . 603 n″ in microphone arrays 602 and 603 are arranged alongmultiple planes. FIG. 6 depicts one exemplary arrangement, wherein themicrophones are arranged across the X-Y plane at a distance D1, and adistance D2 from the demonstration speaker 601. In this way, the spatialdemonstration system may determine characteristics of the demonstrationspeaker 601 at any height, angle, or distance from the speaker.

FIG. 7 is a top-view of microphone array arrangements and positionsaccording to embodiments of the invention. A microphone array may bepositioned at any angle around the demonstration speaker 704. Forexample, microphone array 702 may be positioned directly in front of thedemonstration speaker 704. In other embodiments, microphone array 701may be positioned behind the demonstration speaker (i.e., 270° on theaxis as shown on the diagram). As explained above, frequencies ofacoustic waves disperse from a speaker with a different response gaindepending on their angle of propagation. Microphones may be positionedaround the demonstration speaker such that the response gain may bedetermined over the entire sphere surrounding the speaker.

FIG. 7 further demonstrates that the microphones in microphone arraysmay be arranged along nonlinear planes. Whereas the microphones depictedin FIGS. 3-6 are arranged along a linear (i.e., flat) plane, themicrophones depicted in FIG. 7 (701 a . . . 701 n, 702 a . . . 702 n and703 a . . . 703 n) are arranged along an arcuated curvilinear plane. Oneadvantage of arranging the microphones along the convex or concaveplanes as depicted in FIG. 7 is that the spatial demonstration systemmay capture the output of the speaker at multiple angles over, forexample a constant distance, than a flat microphone array. For example,microphone array 702 may capture speaker output across the rangespanning −30° to 30°.

Another advantage of arranging the microphones along the convex orconcave planes as depicted in FIG. 7 is that the spatial demonstrationsystem may capture how sound disperses throughout different geometriesof rooms. For example, arranging the microphones in along an arcuatedcurvilinear plane as 702 would be ideal for capturing how waves woulddisperse from a demonstration speaker in a semi-circular area, such asan amphitheater.

FIG. 8 is a diagram depicting a microphone array's position overlaidonto a polar plot of a demonstration speaker's directivity pattern. Asthe figure illustrates, the different positions of the microphones 802 a. . . 802 n in the microphone array 802 enable the demonstration systemto measure the different frequency response gains of the speaker atdifferent angles off the speaker's central axis.

FIG. 9 is a block diagram illustrating the characteristics processed andstored by the DSP 902 according to one embodiment of the invention. AsFIG. 9 illustrates the DSP may combine the characteristic 903 of eachmicrophone input signal, INPUT N, INPUT N+1, INPUT N+2, etc, into asingle characteristic 904 representative of the spatial characteristicsof the speaker on the whole. That is, according to one embodiment, theDSP reduces the spatial characteristics of the demonstration speakerinto a spatially averaged characteristic suitable for output on atraditional reference speaker.

One advantage to combining the characteristics into a singlecharacteristic is that the single characteristic may be applied to atraditional reference speaker that contains only a single degree offreedom in the form of a single electrical input. As FIG. 9 shows, theDSP applies the combined characteristic to the input samples 901, andplays the output signal through the reference speaker 905. Because thesingle characteristic considers the spatial features of thedemonstration speaker, the reference speaker provides a more accuratesimulation of the demonstration speaker than traditional approaches.

According to other embodiments of the invention, the acousticcharacteristics are applied to a speaker array, containing multipleindependent speaker elements that replace the traditional referencespeaker to generate an acoustic output simulating the demonstrationspeaker, as illustrated in FIG. 10. The DSP 1002 may utilize eachcharacteristic 1003 N, N+1, N+2, etc., to generate output N, N+1, N+2,etc. Each output drives a single element of the speaker array whoseacoustic responses all combine to simultaneously reproduce how thedemonstration speaker would play the audio input at the microphonepositions associated with N, N+1, N+2, etc. In some embodiments, thespeaker array elements may be arranged in a single dimension (e.g., aline of speakers), in two dimensions (e.g., a speaker face), or in threedimensions. The speakers may be arranged horizontally, vertically, or inany other similar position. In other embodiments, the acousticcharacteristics being applied to the speaker array elements may changein real-time.

FIG. 11 is a block diagram of an exemplary user interface according toan embodiment of the invention. Interface 307 includes options to selectspeakers 1100, select environment 1110, select a sample 1120, provide asample 1130, and build an environment 1140.

Select speakers 1100 allow a user to select demonstration speakers forevaluation. This option may include further suboptions for selecting amake (e.g., a manufacturer like Pioneer) and a model (e.g., Pioneer 1000Series).

Select environment 1110 allows a user to select the demonstrationenvironment. Generally, select environment 1110 relates tocharacteristics that are already determined (computed or measured). Thisoption may provide a textual and/or graphical list of demonstrationenvironments which characteristics are readily accessible to DSP 303.The demonstration environments may be a room or auditorium, or may bethe interior of a vehicle. In that latter scenario, there may besuboptions for selecting a make (e.g., a car manufacturer such as BMW)and a model (e.g., Model 540). Select environment 1110 may allow theuser to modify a demonstration environment or select between variousoptions (e.g., change a room size or select between carpet/no carpet orconvertible/hardtop). Select sample 1120 provides options for theacoustic sample that is played through the virtual demonstration system.Select sample 1120 may include music (portions or the entirety ofsongs), test samples (tones, white noise, etc.), spoken audio, and thelike. Based on the user's selection, select sample 1120 causes the DSP303 to retrieve and process the selected acoustic sample.

Provide sample 1130 allows a user to input his/her own acoustic samplefrom a computer readable storage medium that stores non-transitorysignals, including magnetic storage media (for example, ROMs, floppydiscs, hard disks, etc.), or optically-readable media (for example,CD-ROMs, VDs, etc.). Distinct from computer readable storage medium, auser may input his/her own acoustic sample from a transmission mediathat stores transitory signals, such as data signals embodied in carrierwaves (e.g., the network including the Internet). Provide sample 1130may include submenus for directing the user to insert the computerreadable storage medium into a reader (or connect to the Internet in thecase of transmission media), select the desired acoustic sample (e.g., aportion of a song on track 5), crop the time domain data down to anappropriate size, and so forth.

Build environment 1140 provides an option for a user to build ademonstration environment. For example, this option may allow the userto simulate the room or auditorium in which loudspeakers will be placed.This option may allow the user to compare the performance of variousdemonstration rooms in order to decide which to build in his/her home orbuilding. Build environment 1140 includes submenus so that the user cangraphically build the demonstration room by selecting geometries andmaterials. Materials may automatically be linked to stored acousticabsorption or reflection performance parameters. Once the user has inputthe geometry and material selections, build environment 1140analytically generates the characteristics for the demonstrationenvironment, such as by running a ray trace model or other acousticprediction model.

FIG. 12 is a block diagram of the exemplary characteristics that may beused by the virtual demonstration system. Spatial characteristics 304may include reference speaker characteristics 1200, demonstrationspeaker characteristics 1210, environment characteristics 1220, buildabsorption characteristics 1230, build geometry characteristics 1240,reference characteristics 1250, and microphone array characteristics1260.

In an embodiment of the invention, reference speaker may comprise of anarray of speakers. Reference speaker characteristics 1200 has thecharacteristics of the reference speakers used for the virtualdemonstration system. These characteristics may be a transfer function,impulse response function, or equivalent mathematical description of theacoustic performance of the reference speaker. These characteristics areused to remove the effects of the reference speakers, such as by inversefiltering. Demonstration speaker characteristics 1210 has thecharacteristics of the various demonstration speakers that the virtualsystem is capable of simulating. These characteristics may berepresented similar to those for the reference speakers. Thedemonstration speaker characteristics 1210 are used to insert theeffects of the demonstration speakers, such as by digital filtering(e.g., convolution, infinite impulse response [IIR], or finite impulseresponse [FIR], operations in the time domain or multiplication in thefrequency domain). Environment characteristics 1220 has thecharacteristics of the various demonstration environments that aresupported by the virtual system. This module may also include thecharacteristic of the reference room so that its effects can be removed.

Build absorption characteristics 1230 contains absorption figurescorresponding to various materials. Exemplary absorption parameters areprovided in Chapter 10, Table 10, of Reference Data for Engineers, 9thed. (Butterworth Heinmann, 2002). The materials may be such things ascarpet, hardwood, drapes, and so forth.

Build geometry data 1240 contains selectable geometries (blocks,rectangles, stairs, floors, ceilings, etc.) that can be used in aCAD-CAM like fashion to generate a demonstration environment.

Reference characteristics 1250 contains characteristics of the variousreference environments that are supported by the virtual system.

Microphone array characteristics 1260 contain characteristicsrepresenting attributes of the microphone that affect the recordedsound. These characteristics may include, for example, thesusceptibility to pickup noise and hum, microphone phasing, andsensitivity.

FIG. 13 is a block diagram of the digital signal processing that may beemployed by DSP 303 according to an embodiment of the invention. Becausethe overall acoustic system is treatable as a linear system, theordering of the operations in FIG. 13 can be changed. In block 1300,inverse filtering to remove the contribution or bias of the referencespeakers is performed. In block 1301, the transfer functioncharacteristic of the demonstration speaker is applied. In block 1302,inverse filtering is performed to remove the contribution or bias of thereference room. In block 1303, the transfer function characteristic ofthe demonstration room is applied. In block 1304, the acoustic sample isapplied. In step 1305, various signal conditioning and digital-to-analogoperations are performed before the virtual signal is output at block1306.

It should be understood that the various filtering operations of FIG. 13can be implemented in the time domain (e.g., convolution, infiniteimpulse response [IIR] filter, finite impulse response [FIR] filter) orfrequency domain.

Blocks 1308-1313 illustrate digital processing that may be employed tosimultaneously simulate the temporal and spatial performance of ademonstration speaker, while compensating for any bias attributable tothe characteristics of the reference speakers and/or microphones in anarray. This digital processing may further provide environmentsimulations. In an embodiment of the invention, in Block 1310, inversefiltering may be performed to remove the contribution or bias of thereference speaker, which may be a speaker array.

FIG. 14 is a flow diagram of a method for a user to engage the virtualdemonstration system according to an embodiment of the invention.Because the overall acoustic system is treatable as a linear system, theordering of the operations in FIG. 14 can be changed. In step 1400, theuser accesses the interface. In step 1410, the user selects a make(e.g., Pioneer). In step 1420, the user selects a model (e.g., Series1000). In step 1430, the user can select a demonstration environment forwhich the characteristics are already stored by the virtualdemonstration system. Alternatively, in step 1440 the user can build anenvironment by selecting materials and geometries.

In step 1450, the user can select an acoustic sample to play through thevirtual system. Alternatively, in step 1460 the user can opt to providea sample via a computer readable storage medium that storesnon-transitory signals including magnetic storage media (for example,ROMs, floppy discs, hard disks, etc.) or optically-readable media (forexample, CD-ROMs, VDs, etc.), or transmission media that storestransitory signals, such as data signals embodied in carrier waves(e.g., the network including the Internet). According to one beneficialembodiment, the virtual system includes an option to link to theInternet so that the user can download an acoustic sample.

In step 1470, the user plays the virtual demonstration. In step 1480,the user decides whether to run another virtual demonstration to comparedifferent demonstration speakers and/or different demonstrationenvironments. The virtual system beneficially stores the selections fromthe last run so that they can be used for the next run. For example, theuser will not have to recreate the demonstration environment in run #2.Instead, he/she can simply select the one from the last run. The virtualsystem allows a user to select one or more previously storedconfigurations for a virtual demonstration. The method ends at 1490.

FIG. 15 is a flow diagram of a method creating a virtual demonstrationaccording to an embodiment of the invention. After the method starts at1500, the virtual demonstration system accesses the reference speakercharacteristic at 1510, and applies the reference speaker characteristicat 1520. The application could be performed, for example, by inversefiltering in the frequency domain or time domain.

In step 1530, the virtual system retrieves a characteristiccorresponding to a selected demonstration speaker, and at 1540, thevirtual system applies the retrieved characteristic. This applicationcould be performed, for example, by filtering in the frequency domain ortime domain.

In step 1550, the virtual system accesses and applies environmentalcharacteristics. For example, in step 1552 the reference roomcharacteristic may be applied in order to remove its effects. In step1554, a demonstration environment characteristic corresponding to aselected demonstration environment is retrieved and applied in order toinclude its effects.

In step 1560, the virtual system accesses and applies an acousticsample. For example, in step 1562 a pre-stored acoustic sample that wasselected by the user is applied by the virtual system. For example, instep 1564 a user-supplied (e.g., via computer readable storage medium ortransmission media such as the Internet) acoustic sample is applied bythe virtual system. The application of the acoustic sample could beperformed, for example, by filtering the acoustic sample input with thecharacteristics of the reference speaker and/or demonstration speakerand/or demonstration environment in the time domain or the frequencydomain.

In step 1570, the virtual system performs any ancillary outputprocessing such as digital-to-analog conversion, filtering,amplification, signal conditioning, and so forth, before outputting thevirtual signal to the reference speakers in step 1580.

FIG. 16 is a block diagram of the loudspeaker characteristics andenvironmental characteristics that may be employed for the virtualdemonstration according to an embodiment of the invention. Referencespeaker characteristics 1200 and demonstration speaker characteristics1210 may be empirically determined 1601. The environmentalcharacteristics may be both empirically or analytically determined 1602,as previously discussed.

FIG. 17 is a block diagram of environmental conditions that may beemployed for the virtual demonstration according to an embodiment of theinvention. Environmental conditions 1700 generally represent anadditional set of options that can be selected by the user via interface307. For example, in an embodiment of the invention permitting theenvironmental space to correspond to the interior of a vehicle like acar, environmental conditions 1700 can be used to set variousoperational parameters. For example, environmental conditions 1000 mayallow the user to select a vehicle make 1702, model 1710, speed and/orRPM and/or gear 1720, top and/or roof and/or windows open or closed1730, seating/listening location front/back/left/right 1740, and otherenvironmental factors 1750.

Environmental conditions 1000 permits a user to hear the virtualdemonstration in an acoustic environment of his/her selection. Thisacoustic environment (e.g., a BMW 328i, 50 mph, 4th gear, 3200 RPM,windows closed, driver's seat) is preferably provided by the virtualdemonstration system based on empirical data measurements. This acousticenvironment can be combined with the other components of the overallacoustic system (e. g., demonstration speakers) using conventional DSPprocessing techniques to allow the user to hear the simulatedperformance of the demonstration system in a vehicle in operation.

According to another beneficial aspect of the invention, the virtualdemonstration system can permit a user to experience the simulatedacoustic environment without demonstration speakers or an input acousticsample. In other words, a user may not be interested in stereo equipmentat all. Rather, the user is interested in making a vehicle purchase orlease, and wishes to compare the acoustic performance of competingmodels. Therefore, the virtual demonstration system functions as avirtual environmental factors simulation system. This application isreadily extendible to other vehicles, such as planes (e.g., for flightsimulation), boats (marine simulators), and the like. This applicationis also extendible to non-vehicle products, such as, dishwasher,lawnmower, blender, etc. That is, this application may be used tosimulate sounds created by any system, even if the primary purpose ofthe system is not to create sound.

FIG. 18 is a block diagram of a system for a virtual demonstrationsystem implemented in a retail outlet. The system includes a memory 1830for storing characteristics and acoustic samples, a processor 1820 forperforming DSP processing, a user interface 1810 for allowing a user toselect options, a monitor/CRT 1800 for presenting a visual of thedemonstration speakers, and a data output 1840 for providing data to theuser regarding the virtually demonstrated equipment.

Monitor/CRT 1800 richens the user's experience because he/she now notonly hears the demonstration speaker, but sees them as well. Thepurchase experience is informed not only by what the equipment soundslike, but also by what it looks like. Monitor/CRT 1800 can be anysuitable graphical display for displaying the demonstration speaker,such as a computer display (CRT), television display, and so forth. Ifthe user is getting a demonstration of other equipment, such as anamplifier, monitor/CRT 1800 may display an image of that otherequipment.

Data output 1840 provides data to the user regarding the equipment thatis evaluated. For example, data output 1840 may output thespecifications, product manuals, sales information (cost, financingoptions, sales prices, and the like) and/or pictures (photos orgraphical images) of the equipment. Data output 1840 may be a color orblack-and-white printer or memory output device (disk writer or CDwriter) that can output information to the user who can then take theinformation home to further assess his/her contemplated purchase. Forexample, the user can take photos or graphical images of thedemonstration speakers home to see how well their design blends with theuser's decor at home.

Data output 1840 could also be a device for outputting data regardingthe evaluated equipment to the user electronically over the Internet orvia e-mail. For example, data output 1840 could include or be coupled toa web server for posting information on a web site accessible to theuser. Data output 1840 could include or be coupled to an email serverfor sending an e-mail to the user with the data.

FIG. 19 is a block diagram of an interface for a user to initiate avirtual environmental factors simulation according to an embodiment ofthe invention discussed above for FIG. 17. In FIG. 19, the user canselect a device to be simulated at 1910. For example, a car or plane orother device (make/model). The user can select conditions at 1910(speed/RPM/gear, over torque, ice breaking off propellers,depressurization, etc.). The user can then initiate the virtualenvironmental factors simulation at 1930.

Having described the virtual demonstration system according to severalembodiments, it can be appreciated that numerous benefits flow from theinvention that benefit all three of the consumer, the retailer, and themanufacturer.

The consumer benefits because he/she can listen to and compare multipledemonstration speakers easily and conveniently from the same referencespeaker. The consumer also benefits because the virtual demonstrationprovides a more accurate representation of how the demonstrationspeakers will sound. Therefore, the consumer can make a more informedpurchase decision leading to enhanced customer satisfaction.

The brick-and-mortar retailer benefits because the retailer can use asingle reference speaker set or speaker array to demonstrate theperformance of multiple demonstration speakers, saving costs and space,and allowing the retailer to demonstrate a wider range of products.Because of space limitations, retailers can only display, and thereby,sell a limited number of manufacturer' speakers. This invention allowsretailers to demonstrate and sell a much broader selection ofmanufacturer' speakers.

On-line retailers benefit because the retailer can providedemonstrations at the consumer's home or office that heretofore have notbeen possible. Until now, one of the significant shortcomings of on-linestereo retailing versus traditional in-store retailing was that theon-line retailer had no way to demonstrate its speaker products. Withthe advent of the invention, this is no longer the case and, in fact,the on-line retailer's ability to provide virtual demonstration to theconsumer in the convenience and comfort of the consumer's home may giveon-line retailers an advantage over brick-and-mortar retailers.

Additionally, both on-line and brick-and-mortar retailers also benefitfrom the enhanced customer satisfaction resulting in fewer returns andmore repeat business.

Manufacturers also benefit from the invention. Manufacturers benefitfrom enhanced customer satisfaction. Manufacturers also benefit becausethe invention provides a means for displaying and demonstrating a widervariety of the manufacturer's product line at retailers.

As it should be clear to those of ordinary skill in the art, furtherembodiments of the present invention may be made without departing fromits teachings and all such embodiments are considered to be within thespirit of the present invention.

For example, the reference speakers of the virtual demonstration systemcould easily be replaced by high-end headphones so that the user wouldnot need a reference room to experience the virtual demonstration. Thisembodiment is especially advantageous because it would remove thenecessity for accounting for the bias imparted by a reference listeningroom. Referring to FIG. 13, block 1302 for filtering to remove theeffects of the reference room would not be required because effectivelythere would be no reference room if headphones are used as the referencespeakers. Further, if headphones are used as the reference speakers, thevirtual demo may be delivered to a remote location, such as to a user'scomputer over the internet.

Reference headphones could be used in the virtual demonstration systemto demonstrate demonstration headphones. Thus, one set of high-qualityreference headphones could be used to virtually demonstrate theperformance of multiple sets of headphones.

It should also be understood that the virtual demonstration system couldbe implemented in a wide variety of contexts beyond the traditionalelectronics retail outlet. Some of these venues have been describedabove (churches, auditoriums, etc.). Depending on the product, othervenues that would benefit from the invention may include car,motorcycle, recreational vehicle (RV), and boat outlets; trade shows andsimilar public shows (e.g., auto shows, boat shows, home/commercialbuilder shows, home goods show etc.).

As suggested above, the invention can be considered to have two basicaspects: a virtual product performance aspect (for demonstrating theperformance of, for example, electronics equipment like speakers,amplifiers, and the like) and a virtual environmental factors simulationaspect (for simulating various acoustic environments, like the noiseinside of a car or plane during operation). The virtual productperformance aspect may demonstrate performance of any product that mayproduce sound, such as, a speaker, dishwasher, engine, etc. The virtualenvironmental factors simulation aspect may simulate acousticenvironments (e.g., room, vehicle, outdoors, etc.) and operationalfactors (e.g., speed, windows up/down, other running equipment, HVAC,and other factors that may modify the perception of the sound comingfrom the product that the application is trying to simulate). In somecases, an application will involve both aspects of the invention, suchas when a consumer desires to hear the performance of a set ofdemonstration speakers (virtual product performance aspect) in a BMW328i at 50 m.p.h., 3000 RPM, 4th gear, with the windows open (virtualenvironmental factors simulation aspect).

In other cases, an application will involve only one aspect of theinvention, such as when a consumer wishes to evaluate or experience theacoustic conditions of various cars, planes, boats, and the like. Forexample, the consumer may wish to compare noise levels in cars duringvarious operating conditions, as previously discussed. The consumer maywish to compare noise levels for various options for a given car, suchas a six-cylinder engine versus eight-cylinder engine, stick shiftversus automatic, wide sport tires versus standard tires, convertibleversus hardtop, headlights up versus down, windows up versus down, topup versus closed, and so forth. In another context, outboard enginemanufacturers or retailers can use the virtual environmental factorssimulation aspect of the invention in order to provide a simulation ofengine noise for a boat in operation. The system would allow selectionof various options which characteristics would be processed to generatea simulated noise output. The various options could include such thingsas engine type, boat type/shape/geometry, speed, RPM, sea state (waveheight), two-cycle versus four-cycle engine, various power settings,various locations in the boat (forward, aft, left, right, deck, below),distance from shore, and so forth.

Other examples of applications for virtual environmental factorssimulation might be found in other consumer, educational, regulatory,and industrial applications. As just one example, active noisecancellation (ANC) is now finding application in consumer and industrialsettings. The virtual environmental factors simulation aspect of thepresent invention would find beneficial application to demonstrating theefficacy of active noise cancellation. For example, a firm developingand marketing high-end active noise cancellation technology to largeindustry companies would obviously benefit from being able todemonstrate the improvement in noise levels that an ANC installationwould bring.

As suggested above, the virtual demonstration system software could bepackaged for use in a home or office using high quality referencespeakers or headphones. The software could be provided by disk or othercomputer readable storage media or, alternatively, could be madeavailable for download over the Internet. For so-called “on-line”retailers not having traditional “brick & mortar” outlets, thisembodiment could be extremely beneficial. Preferably, this embodimentwould include interface options for selecting the type of referencespeakers or headphones to be used for specific users so that theireffects can be compensated. In a further variation to this approach, theuser could use high performance reference speakers in the form offree-standing speakers (e.g., floor speakers, speakers on a stand,bookshelf speakers, etc.) or headphones provided by the retailer oranother entity (e.g., club, friend, speaker manufacturer, otherbusiness, band, etc.). This embodiment has the advantage that the userneed not own any special equipment to experience the virtualdemonstration in the comfort of his/her home or office using basiccomputer hardware, such as a personal computer.

According to a further variation of the invention, virtual demonstrationsoftware could be run by the user in conjunction with basic homespeakers for virtually demonstrating car audio speakers. Most basic homespeakers will have adequate acoustic performance to simulate theperformance of car speakers. Thus, a user could practice the inventionin accordance with the exemplary embodiments of FIGS. 11, 14, 17, and19, in order to virtually demonstrate the performance of car speakers inan operational environment (make/model of car, speed, RPM, windowsup/down, etc.).

According to yet another variation, a retailer, audio systemscontractor, or other business (“demonstrator”) could use the virtualdemonstration system of the invention in order to provide on-sitedemonstrations of various demonstration speakers under differentenvironmental conditions. For example, a demonstrator could bringportable versions of the virtual demonstration system with a set ofreference speakers to a place of worship, auditorium, home, office,industrial facility, club, theater, school, or the like in order todemonstrate performance of various demonstration speakers and otherequipment (e.g., amplifiers of varying grades and powers). In such acase, the user interface may provide an option to exclude anycompensation for environment because no reference environment is beingused and no demonstration environment is selected. Rather, the actuallistening environment is being used.

In some cases, a customer would request that the demonstration takeplace in a room or building that is not completed so that an interimassessment can be made. Such an interim assessment could includevirtually demonstrating the impact of various materials (e.g.,furniture, acoustic tile and panels, carpeting, drapery, etc.) so thatthe customer could make decisions on material selection based onexpected acoustic performance. Such an interim assessment might entailthe measurement or prediction of the transfer characteristic (or impulseresponse) of the existing space where the demonstration would takeplace.

Additionally, while the reference speakers are generally discussed interms of pairs of speakers, the virtual demonstration system couldeasily employ further speakers so that a fully immersive acousticexperience could be simulated.

Additionally, the build environment feature of the invention can be maderelatively simple or complex depending on the sophistication and needsof the average user. For example, the user may be asked to identify thepercentage of wall surfaces using highly reflective materials (e.g.,glass, wood paneling, untreated drywall, etc.), the percentage of wallsurfaces covered with absorptive materials (e.g., curtains or fabricwall art), the nature of the floor material (e.g., wood, vinyl, orcarpet), the composition of the ceiling (e.g., acoustic tile, woodpaneling or drywall), the ceiling design (e.g. flat or cathedral), thedensity of upholstered furniture (e.g., high, medium, or low), and/orthe shape of the room. Additionally, it should be understood that thecomponents of the virtual demonstration system need not be collocated inone place. For example, referring to FIG. 3, an implementation at aretail outlet may have the interface 307, DSP 303, and referencespeakers 306 in a listening room, while the spatial characteristics 304and samples 305 may be remotely located. For example, thecharacteristics 304 and/or samples 305 may be located at one or more websites or non-Internet remote servers maintained by the retailer or bythe manufacturers. If maintained by the manufacturers, this beneficialembodiment would allow manufacturers to update and revise theirdemonstration speaker characteristics as they change or as new modelsare released to market.

In a similar variation where the user is a consumer at home or at abusiness site, the interface 307, DSP 303 and reference speakers 306 areat the user's remote site, while the characteristics are maintained bythe retailer and/or a manufacturer at a web site or non-Internet remoteserver.

For typical retailers having stores with listening rooms, the inventioncould be beneficially applied so that each manufacturer would need tosupply only their best, top-of-the-line speaker. This speaker could beused as the reference speaker for that manufacturer, and the various DSPoperations and demonstration characteristics could be applied tovirtually demonstrate the manufacturer's other speakers through thetop-of-the-line model. This application would allow each manufacturer todemonstrate the entire line, while allowing the retailer to savevaluable floor space.

Additionally, it should be understood that the various operations arepresented so as to best explain the invention in a clear manner. Theseoperations could easily be further divided or combined. For example, inFIG. 13 the filtering operations for the reference speakers (block 1300)and the demonstration speakers (block 1301) could easily be combinedinto a single operation.

Therefore, it is intended that all matter contained in above descriptionor shown in the accompanying drawings shall be interpreted as exemplaryand not limiting, and it is contemplated that the appended claims willcover any other such embodiments or modifications as fall within thetrue scope of the invention.

Generally, it should be noted that the components depicted and describedherein above may be, or include, a computer or multiple computers.Although the components are shown as discrete units, all components maybe interconnected or combined. The components may be described in thegeneral context of computer-executable instructions, such as programmodules, being executed by a computer. Generally, program modulesinclude routines, programs, objects, applications, components, datastructures, etc., that perform particular tasks or implement particularabstract data types.

Those skilled in the art will appreciate that the invention may bepracticed with various computer system configurations, includinghand-held wireless devices such as mobile phones, tablets or PDAs,multiprocessor systems, microprocessor-based or programmable consumerelectronics, minicomputers, mainframe computers, and the like. Theinvention may also be practiced in distributed computing environmentswhere tasks are performed by remote processing devices that are linkedthrough a communications network. In a distributed computingenvironment, program modules may be located in both local and remotecomputer storage media including memory storage devices.

Mobile computers typically include a variety of computer readable mediathat can form part of the system memory and be read by the processingunit. By way of example, and not limitation, computer readable media maycomprise computer storage media. The system memory may include computerstorage media in the form of volatile and/or nonvolatile memory such asread only memory (ROM) and random access memory (RAM). A basicinput/output system (BIOS), containing the basic routines that help totransfer information between elements, such as during start-up, istypically stored in ROM. RAM typically contains data and/or programmodules that are immediately accessible to and/or presently beingoperated on by a processing unit. The data or program modules mayinclude an operating system, application programs, other programmodules, and program data. The operating system may be or include avariety of operating systems such as the Macintosh® OS or iOS operatingsystems, Microsoft Windows® operating system, the Unix operating system,the Linux operating system, the Xenix operating system, the IBM AIX™operating system, the Hewlett Packard UX™ operating system, the NovellNetware™ operating system, the Sun Microsystems Solaris™ operatingsystem, the OS/2™ operating system, the BeOS™ operating system, theApache™ operating system, an OpenStep™ operating system or anotheroperating system of platform.

At a minimum, the memory includes at least one set of instructions thatis either permanently or temporarily stored. The processor executes theinstructions that are stored in order to process data. The set ofinstructions may include various instructions that perform a particulartask or tasks, such as those shown in the appended flowchart. Such a setof instructions for performing a particular task may be characterized asa program, software program, software, engine, module, component,mechanism, or tool. The computer may include a plurality of softwareprocessing modules stored in a memory as described above and executed ona processor in the manner described herein. The program modules may bein the form of any suitable programming language, which is converted tomachine language or object code to allow the processor or processors toread the instructions. That is, written lines of programming code orsource code, in a particular programming language, may be converted tomachine language using a compiler, assembler, or interpreter. Themachine language may be binary coded machine instructions specific to aparticular computer.

Any suitable programming language may be used in accordance with thevarious embodiments of the invention. Illustratively, the programminglanguage used may include assembly language, Ada, APL, Basic, C, C++,COBOL, dBase, Forth, FORTRAN, Java, Modula-2, Pascal, Prolog, REXX,and/or JavaScript, for example. Further, it is not necessary that asingle type of instruction or programming language be utilized inconjunction with the operation of the system and method of theinvention. Rather, any number of different programming languages may beutilized as is necessary or desirable.

In addition, the instructions and/or data used in the practice of theinvention may utilize any compression or encryption technique oralgorithm, as may be desired. An encryption module might be used toencrypt data. Further, files or other data may be decrypted using asuitable decryption module.

The computing environment may also include other removable/nonremovable,volatile/nonvolatile computer readable storage media that storesnon-transitory signals. For example, a hard disk drive may read or writeto nonremovable, nonvolatile magnetic media. A magnetic disk drive mayread from or write to a removable, nonvolatile magnetic disk, and anoptical disk drive may read from or write to a removable, nonvolatileoptical disk such as a CD ROM or other optical media. Otherremovable/nonremovable, volatile/nonvolatile computer storage media thatcan be used in the exemplary operating environment include, but are notlimited to, magnetic tape cassettes, flash memory cards, digitalversatile disks, digital video tape, solid state RAM, solid state ROM,and the like. The computer readable storage media is typically connectedto the system bus through a removable or non-removable memory interface.

Distinct from computer readable storage medium, the computingenvironment may also include transmission media that stores transitorysignals. For example, transmission media may include data signalsembodied in carrier waves or digital data packets (e.g., transmittedthrough a network).

The processing unit that executes commands and instructions may be ageneral purpose computer, but may utilize any of a wide variety of othertechnologies including a special purpose computer, a microcomputer,mini-computer, mainframe computer, programmed microprocessor,micro-controller, peripheral integrated circuit element, a CSIC (VisitorSpecific Integrated Circuit), ASIC (Application Specific IntegratedCircuit), a logic circuit, a digital signal processor, a programmablelogic device such as an FPGA (Field Programmable Gate Array), PLD(Programmable Logic Device), PLA (Programmable Logic Array), RFIDprocessor, smart chip, or any other device or arrangement of devicesthat is capable of implementing the steps of the processes of theinvention.

It should be appreciated that the processors and/or memories of thecomputer system need not be physically in the same location. Each of theprocessors and each of the memories used by the computer system may bein geographically distinct locations and be connected so as tocommunicate with each other in any suitable manner. Additionally, it isappreciated that each of the processors and/or memory may be composed ofdifferent physical pieces of equipment.

A user may enter commands and information into the computer through auser interface that includes input devices such as a keyboard andpointing device, commonly referred to as a mouse, trackball or touchpad. Other input devices may include a microphone, joystick, game pad,satellite dish, scanner, voice recognition device, keyboard, touchscreen, toggle switch, pushbutton, or the like. These and other inputdevices are often connected to the processing unit through a user inputinterface that is coupled to the system bus, but may be connected byother interface and bus structures, such as a parallel port, game portor a universal serial bus (USB).

One or more monitors or display devices may also be connected to thesystem bus via an interface. In addition to display devices, computersmay also include other peripheral output devices, which may be connectedthrough an output peripheral interface. The computers implementing theinvention may operate in a networked environment using logicalconnections to one or more remote computers, the remote computerstypically including many or all of the elements described above.

Various networks may be implemented in accordance with embodiments ofthe invention, including a wired or wireless local area network (LAN)and a wide area network (WAN), wireless personal area network (PAN) andother types of networks. When used in a LAN networking environment,computers may be connected to the LAN through a network interface oradapter. When used in a WAN networking environment, computers typicallyinclude a modem or other communication mechanism. Modems may be internalor external, and may be connected to the system bus via the user-inputinterface, or other appropriate mechanism. Computers may be connectedover the Internet, an Intranet, Extranet, Ethernet, or any other systemthat provides communications. Some suitable communications protocols mayinclude TCP/IP, UDP, or OSI, for example. For wireless communications,communications protocols may include Bluetooth, Zigbee, IrDa, Wi-Fi, 2G,3G, Ultra-Wideband and Long Term Evolution (LTE) or other suitableprotocols. The wireless communications protocol may also includeshort-range communications devices and protocols, such as RFID, orNear-Field Communication radio transmissions. Furthermore, components ofthe system may communicate through a combination of wired or wirelesspaths.

Although many other internal components of the computer are not shown,those of ordinary skill in the art will appreciate that such componentsand the interconnections are well known. Accordingly, additional detailsconcerning the internal construction of the computer need not bedisclosed in connection with the present invention.

The various embodiments and features of the presently disclosedinvention may be used in any combination, as the combination of theseembodiments and features are well within the scope of the invention.While the foregoing description includes many details and specificities,it is to be understood that these have been included for purposes ofexplanation only, and are not to be interpreted as limitations of thepresent invention. It will be apparent to those skilled in the art thatother modifications to the embodiments described above can be madewithout departing from the spirit and scope of the invention.Accordingly, such modifications are considered within the scope of theinvention as intended to be encompassed by the following claims andtheir legal equivalents.

1. A system for simulating acoustic performance of speakers, comprising:at least one reference speaker; a user interface; at least one storagemedium storing electronic data representing spatial audiocharacteristics reflecting acoustic responses for at least onedemonstration speaker measured at multiple points in space according oneor more of (a) a varying angle with respect to the at least onedemonstration speaker, (b) a varying distance from the at least onedemonstration speaker, and (c) a varying height with respect to the atleast one demonstration speaker; at least one computer processorconfigured to: receive, via said user interface, a first user selectionof a first demonstration speaker; retrieve, from said storage medium,electronic data representing spatial audio characteristics of said firstdemonstration speaker; simulate acoustic performance of said firstdemonstration speaker by applying said spatial audio characteristics ofsaid first demonstration speaker to an acoustic sample to generate afirst simulated acoustic output; and output said first simulatedacoustic output via said at least one reference speaker.
 2. The systemof claim 1, wherein the spatial audio characteristics arethree-dimensional characteristics that reflect the acoustic responseaccording to multiple points in three dimensional space.
 3. The systemof claim 1, wherein said spatial audio characteristics for multiplepoints in space comprise at least one combined spatial audiocharacteristic created by combining spatial audio characteristics formultiple points in space for a given demonstration speaker.
 4. Thesystem of claim 1, wherein said at least one computer processor isfurther configured to determine filter coefficients used to simulate theperformance of the at least one demonstration speaker.
 5. The system ofclaim 1, wherein said spatial audio characteristics comprise transferfunctions or impulse responses.
 6. The system of claim 1, wherein saidat least one computer processor is further configured for a user toselect multiple different demonstration speakers in order to comparetheir performance.
 7. The system of claim 1, wherein said at least onereference speaker comprises an array of speakers.
 8. The system of claim1, wherein said at least one storage medium further stores electronicdata representing selectable geometries and materials used to create ademonstration environment, said demonstration environment reflected byan acoustic characteristic applied to simulate the performance of theselected first demonstration speaker in said demonstration environment.9. The system of claim 1, wherein said at least one storage mediumfurther stores electronic data representing the audio characteristics ofsaid at least one reference speaker that is applied to mitigate the biasof the at least one reference speaker in the simulated acoustic output.10. The system of claim 1, wherein the at least one reference speakercomprises headphones.
 11. A computer-implemented method of providingsimulated acoustic performance of speakers, comprising: providing atleast one reference speaker; storing in at least one storage mediumelectronic data representing spatial audio characteristics reflectingacoustic responses determined for multiple points in space for at leastone demonstration speaker reflecting one or more of (a) a varying anglewith respect to the at least one demonstration speaker, (b) a varyingdistance from the at least one demonstration speaker, and (c) a varyingheight with respect to the at least one demonstration speaker; receivinga user selection of a first demonstration speaker; retrieving thespatial audio characteristics for said selected first demonstrationspeaker; processing by at least one computer processor the retrievedspatial audio characteristics of said selected first demonstrationspeaker with an acoustic sample to generate a first simulated acousticoutput; and outputting the first simulated acoustic output using said atleast one reference speaker.
 12. The computer-implemented method ofclaim 11, wherein the spatial audio characteristics arethree-dimensional characteristics that reflect the acoustic responseaccording to multiple points in three dimensional space.
 13. Thecomputer-implemented method of claim 11, wherein said spatial audiocharacteristics comprise at least one combined spatial audiocharacteristic created by combining spatial audio characteristics formultiple points in space for a given demonstration speaker.
 14. Thecomputer-implemented method of claim 11, wherein said at least onecomputer processor is further configured to determine filtercoefficients used to simulate the performance of the at least onedemonstration speaker.
 15. The computer-implemented method of claim 11,wherein said spatial audio characteristics comprise transfer functionsor impulse responses.
 16. The computer-implemented method of claim 11,wherein said at least one computer processor is configured for a user toselect multiple different demonstration speakers in order to comparetheir performance.
 17. The computer-implemented method of claim 11,wherein said at least one reference speaker comprises an array ofspeakers.
 18. The computer-implemented method of claim 11, wherein saidat least one storage medium further stores electronic data representingselectable geometries and materials used to create a demonstrationenvironment, said demonstration environment reflected by an acousticcharacteristic applied to simulate the performance of the selected firstdemonstration speaker in said demonstration environment.
 19. Thecomputer-implemented method of claim 11, wherein said at least onestorage medium further stores electronic data representing the audiocharacteristics of said at least one reference speaker that is appliedto mitigate the bias of the at least one reference speaker in thesimulated acoustic output.
 20. The computer-implemented method of claim11, wherein the at least one reference speaker comprises headphones.